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[Phil (PJ) Berks]

A little more guidance needed please.
I have recently refurbished my carb with our host’s fine Jap made kit. At the same time I ditched the PAV and sealed off the orifices as required, also I have fitted the Tea Caddy air filter with standard gauze filter. I have also renewed the points and condenser and checked/adjusted the timing.



Looking at the plug after a 20 mile run it looks a little week and the engine seems a little hesitant at times when accelerating unless you go for full bore. Should I go one size up on all jets or just the pilot jet and main – tick over is steady and solid, however it does miss a bit under normal load conditions when cold until it is thoroughly warm.....Many thanks Phil (PJ)

[Alan R]

around

[PeteF]

If it's pulling OK at foll throttle it would indicate your main jet is OK. I'd lift the needle one notch first and see what results you get.

[Dampking]

If it's a Mikarb then I usually run them at the richest settings that is the last notch, raising the needle.

[Phil (PJ) Berks]

PeteF and Dampking, thank you for that, I shall try it as soon as this weather clears up a bit and I will share the results.... AlanR: Was there more text in your reply other than “around”? Many thanks thus far.Phil(PJ)

[Riggers]

Hi Phil. Just to help you along the way and maybe save you a quid or two here are a few tips learned from bitter experience. The pilot jet simply controls tickover. Slide cut away eases you onto the needle jet. The needle position will allow a degree of enrichening but ulimately you may need a larger needle jet. On standard gearing (17 tooth gearbox) the needle jet controls things from just off tickover until about 50mph in top. After 50mph the main jet kicks in. This is obviously an 'approx' as things like hills and very heavy winds or a pillion passenger can vary the load on the engine and thus the throttle opening. Hope this helps. Cheers.

[Alan R]

-----------OOH - er!! I wonder where all that lot went to then ??..... Yes, there was a reply with all the usual pertinent, smart, jovial, technical points----but I've been to sleep since then ( and had to go home in the morning !!)and I can't remember exactly what I'd put in it..... So, re-reading your posting it does seem as if mid-range could be richened up a tad (--easy job first is RAISE the needle 1 notch and re-test....... When on a "test run" take your plug wrench with you AND a couple of spare, clean plugs (of the correct grade, naturally)......Get the engine up to FULL RUNNING TEMP ---anything less is of no use..... Do your plug-chop in 3rd gear going up a fairly steep hill (I go out into the rural countryside)-- taking the eng. up to full revs. and hold for a few moments (as if you were just about to change gear---).. then switch off---stop and remove the plug as quick as poss. Compared to doing it on a flat road you will probably find that you'll need to go up on main jet ( by increments of 5% )....A light, chocolate brown is technically correct but I prefer it to be a slightly DARKER shade ie it's erring slightly on the rich side. My classic 500 (19T) returns around 80mpg overall on club runs with some prolonged 60mph periods plus hills ( Central Wales) thrown in. And that's with a tea caddy (standard filter)---28mm MIKCARB ( with RIGGERS Jetting) and re-built( 6" shorter) standard silencer.

[Riggers]

Hey Alan R. All this about jetting carbs brings something back to me. A few months ago (nay maybe a year) a guy on here had a mysterious carb problem and you (very generously IMHO) said you'd send him a fully set up carb. What was the outcome mate? If it's not publishable I'd still like to know on [email protected] . Cheers Riggers.

[Bullet Train]

Riggers, Good Morning.
Check my postings and Youtube too! All the stuff I've tried, with Alan R's help, and others on this group, is updated there.
Regards
Bullet Train